1. Field of the Invention
The present invention relates to a radioactive sample holder for holding a syringe containing a radioactive sample, the radioactive sample holder being adapted to be loaded into a radioactivity measuring apparatus for measuring an amount of radioactivity of the radioactive sample.
2. Description of the Related Art
There have been developed a method of and an apparatus for measuring a level of radiation emitted from a radioactive sample that is administered to an examinee and which concentrates on a certain body region of the examinee, thereby inspecting the state of the examinee.
The radioactive sample is usually introduced from a radioactive sample dispenser (see Japanese Patent Publication No. 3-31468) into a syringe, and then administered from the syringe to the examinee. For accurately inspecting the state of the examinee, it is necessary to supply the syringe with a sufficient amount of radioactive sample. A radioactivity measuring apparatus disclosed in a catalog entitled “CURIEMETER IGC-7” (issued by ALOKA CO., LTD. in September, 2000) has been developed for measuring an amount of radioactivity of the radioactive sample held in the syringe.
The disclosed radioactivity measuring apparatus utilizes an ionizing action of radiation emitted from the radioactive sample. As shown in FIG. 16 of the accompanying drawings, a syringe 2 containing a radioactive sample therein is held by a holder 4, which is inserted into a hollow cylindrical detector 6 having a built-in sensor for measuring a level of radiation emitted from the radioactive sample.
The holder 4 has an engaging arm 8 disposed on its upper end for engaging an upper open end of the detector 6. The holder 4 also has a holder ring 12 for holding the syringe 2, the holder ring 12 being mounted on the lower end of a shaft 10 extending vertically downwardly from the engaging arm 8. The syringe 2 has a hollow cylinder 14 including a flange 16 on its upper end and a needle 18 extending downwardly from the lower end of the hollow cylinder 14. The syringe 2 is held by the holder ring 12 with the flange 16 resting on an upper surface of the holder ring 12 and the needle 18 extending downwardly.
When the syringe 2 is held by the holder ring 12 with the needle 18 extending downwardly, the radioactive sample contained in the syringe 2 may possibly leak out through the needle 18. Usually, a plurality of syringes 2 of different sizes containing respective different amounts of the radioactive sample are provided for use with the radioactivity measuring apparatus. In order to hold the different syringes 2, the radioactivity measuring apparatus must have a plurality of holders 4 having respective holder rings 12 with different sizes matching the sizes of each of the syringes 2. In addition, as shown in FIG. 16, when the exposed syringe 2 is to be inserted into the detector 6, the operator needs to exercise adequate care in handling the syringe 2 to avoid exposure to the radioactive sample contained in the syringe 2.